Clustering of class IHLA oligomers with CD8 and TCR:: Three-dimensional models based on fluorescence resonance energy transfer and crystallographic data
Clustering of class IHLA oligomers with CD8 and TCR:: Three-dimensional models based on fluorescence resonance energy transfer and crystallographic data
复制标题
DOI：
10.4049/jimmunol.166.8.5078
复制
发表时间：
2001-04-15
影响因子：
4.4
通讯作者：
Damjanovich, S
中科院分区：
文献类型：
--
作者：
Gaspar, R;Bagossi, P;Damjanovich, S
荧光共振能量转移（FRET）的数据，根据横向迁移率测量，建议存在的I类HLA二聚体和低聚体在活的人类细胞，包括B淋巴母细胞细胞系（JY）在本研究中使用的表面。使用荧光团缀合的分别针对结构良好表征的重链和轻链表位的mAb W 6/32和L368的Ag结合片段，通过FRET在JY B细胞上测量分子内和分子间I类HLA表位距离。这些表位相对于膜结合的BODIPY-PC（2-（4，4-二氟-5-（4-苯基-1，3-丁二烯基）-4-硼杂-3a，4a-二氮杂-s-引达省-3-戊酰基）-1-十六酰基-sn-甘油基-3-磷酸胆碱）的平面外位置也通过FRET测定。计算机模拟对接的晶体结构的I类HLA和表位特异性Ag结合片段，与实验确定interpitope和表位细胞表面的距离作为限制，揭示了几个空间上允许和FRET兼容的I类HLA二聚体和四聚体的安排。扩展具有相互作用的TCR和CD 8的四聚体I类HLA模型导致超分子簇的模型，所述超分子簇可能生理上存在并且充当CD 8-HLA-I复合物网络的功能上重要的单元，所述复合物网络甚至在效应子和APC的界面处的低MHC-肽浓度下提供增强的信号传导效率。免疫学杂志，2001年。
Fluorescence resonance energy transfer (FRET) data, in accordance with lateral mobility measurements, suggested the existence of class I HLA dimers and oligomers at the surface of live human cells, including the B lymphoblast cell line (JY) used in the present study. Intra- and intermolecular class I HLA epitope distances were measured on JY B cells by FRET using fluorophore-conjugated Ag-binding fragments of mAbs W6/32 and L368 directed against structurally well-characterized heavy and light chain epitopes, respectively. Out-of-plane location of these epitopes relative to the membrane-bound BODIPY-PC (2-(4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexadecanoyl-sn-glycero-3-phosphocholine) was also determined by FRET. Computer-simulated docking of crystallographic structures of class I HLA and epitope-specific Ag-binding fragments, with experimentally determined interepitope and epitope to cell surface distances as constraints, revealed several sterically allowed and FRET-compatible class I HLA dimeric and tetrameric arrangements. Extension of the tetrameric class I HLA model with interacting TCR and CD8 resulted in a model of a supramolecular cluster that may exist physiologically and serve as a functionally significant unit for a network of CD8-HLA-I complexes providing enhanced signaling efficiency even at low MHC-peptide concentrations at the interface of effector and APCs. The Journal of Immunology, 2001.